FIG. 16 shows a structural example of a video transmission system for transmitting a picture from its transmitting side to receiving side.
On the transmitting side, in a high definition video camera 201, an object is imaged and a high definition picture formed of 1920×1035 pixels in horizontal by longitudinal in the 16:9 aspect ratio (hereinafter, it is preferably referred to as HD picture) is outputted, for example. The HD picture for approximately 30 frames will be normally outputted per second from the video camera 201. But here the HD picture is subjected to interlaced scanning. Therefore, the HD picture for approximately 60 fields is outputted per second from the video camera 201.
On the transmitting side, in a standard or low definition video camera 202, an object is imaged and a standard or low definition picture in the 4:3 aspect ratio (hereinafter, it is preferably referred to as SD picture) is outputted, for example. If the video camera 202 is in the national television system committee (NTSC) system or the phase alternation by line (PAL) system, one frame is formed of 720×480 pixels or 720×576 pixels respectively and the number of frames per second (the number of fields) is 30 (60) or 25 (50) respectively, for example.
On the transmitting side, in a progressive imager 203, an object is scanned and the scanned picture (hereinafter, it is preferably referred to as progressive picture) is sequentially outputted. And on the transmitting side, in a computer 204, a picture formed of, e.g., 640×480 pixels is generated and outputted as computer graphics (CG).
The ratio in horizontal to longitudinal of pixels that compose pictures to be outputted by the video cameras 201 and 202 is approximately 1:1.1. The ratio in horizontal to longitudinal of pixels that compose a picture to be outputted by the computer 204 is 1:1.
As the above, pictures different in its aspect ratio, the number of pixels, its scanned method, the ratio of pixels in horizontal and longitudinal, etc., will be outputted from the video cameras 201 and 202, progressive imager 203 and computer 204.
These pictures are inputted to an editor 205. In the editor 205, pictures from the video cameras 201 and 202, progressive imager 203 and computer 204 are edited respectively. All the edited pictures are converted into progressive pictures formed of, e.g., 1920×1080 pixels and outputted to a source encoder 206. In the source encoder 206, the pictures outputted from the editor 205 is coded (MPEG-coded) based on the moving picture experts group (MPEG) standard for example, and thus obtained coded data is supplied to a channel encoder 207.
The adoption of that converting all of pictures different in the number of pixels, its scanned method, etc., into 1920×1080-pixel progressive pictures by advanced television (ATV) has been planned.
In the channel encoder 207, channel coding is performed to improve the reliability of the coded data in transmission. That is, in the channel encoder 207, e.g., error correcting codes (ECCs) are added to the coded data as processing for error correction, and further it is subjected to prescribed modulation or the like. The transmit data obtained by the processing in the channel encoder 207 is transmitted via a transmission line 211.
On the receiving side, the transmit data transmitted from the transmitting side as the above is received. This transmit data is supplied to a channel decoder 208 to be channel-decoded. Specifically, prescribed demodulation is performed and further error correction using the ECCs or the like is performed, for example.
The coded data obtained as a result of the processing in the channel decoder 208 is supplied to a source decoder 209. In the source decoder 209, the coded is expanded by, for example, decoded (MPEG-decoded) based on the MPEG standard, and thus obtained picture data is supplied to a processor 210.
In the processor 210, the picture data from the source decoder 209 is processed to be matched to the format of an output device to output the picture data. That is, in the case where the picture data is displayed in an HD display device 221 for displaying HD pictures, in the processor 210, the picture data outputted by the source decoder 209 is processed into an interlace-scanned HD picture composed of, e.g., 1920×1035 pixels in the 16:9 aspect ratio. In the case where the picture data displayed in an SD display device 222 for displaying SD pictures, in the processor 210, the picture data outputted by the source decoder 209 is processed into an SD picture in the NTSC system or the PAL system, composed of 720×480 pixels or 720×576 pixels for example. In the case where the picture data is printed out by a printer 223, in the processor 210, the picture outputted by the source decoder 209 is converted into a picture of which the ratio of pixels in horizontal to longitudinal is corresponded to the printer 223. On the other hand, in the case where the picture data is displayed on a computer display 224, in the processor 210, the picture data outputted by the source decoder 209 is processed into a picture composed of 640×480 pixels for example.
In the HD display device 221, the SD display device 222, the printer 223 and the computer display 224, the picture from the processor 210 is displayed or printed out.
By the way, heretofore, the editing processing by the editor 205, the compression processing by the source encoder 206 and the channel coding processing by the channel encoder 207 on the transmitting side have quasi conducted respectively and independently.
For example, the compressed data has less information amount than the data before compression processing. Thus, if the compressed data can be set to be edited, a load on the editor 205 can be reduced. However, if the picture is MPEG-coded in the source encoder 206 as described above, the bit stream obtained as its result becomes difficult to be edited unless in a group of picture (GOP) unit, and editing of that is limited to so-called cut editing by only connecting the GOPs. Since compression processing regardless of the editing processing by the editor 205 is performed in the source encoder 206, the compressed data cannot be edited in a frame unit and it is difficult to give various effects on it.
Moreover, for example, in the source encoder 206, compression processing is not performed in consideration of the addition of ECCs by the channel encoder 207. Therefore, for example, if ECCs are added to the coded data obtained by the compression processing, sometimes compressibility as the entire data after the addition of ECCs has deteriorated.
As the above, heretofore, since the processing necessary for picture coding, e.g., the editing processing, compression processing and channel coding processing, etc., has not performed in consideration of the other processing, it has been difficult to perform efficient processing.